The present invention relates to an interface circuit for a thin display, e.g., a liquid crystal display, EL display, a plasma display or a LED display. More particularly, the present invention relates to a color display device having an interface circuit which can be used as a compact and lightweight display device by utilizing the interface signals of CRT displays that have gained a wide application particularly in personal computers.
The present invention relates to an interface circuit which can play the role of a color display interface in the same driving circuit construction as those of the prior art devices by utilizing interface signals of a CRT display, storing independent color display data in independent RAMs and converting the display data into mixed display data of red, green and blue at the time of read-out.
Liquid crystal display devices have the characterizing features in that they are thin, operate at a low voltage and consume less power. Therefore, they have been put into practical application recently to terminal display devices of personal computers, word processors, and the like, by use of a large dot matrix panel. Nowadays LSI circuits that can be connected directly to CRT interfaces as portable computers have been developed and manufacturers of various office automation equipment have produced interface circuits that are used exclusively for liquid crystal display devices, by means of gate arrays. For these reasons, there exist vigorous demands for the liquid crystal display devices. Although these liquid crystal display devices have a display capacity of such as 640.times.200 dots that can replace CRT, they are generally monochoric display and are not sufficient in terms of display information quantity when used for graphic illustration. In addition, they are not sufficiently attractive because they merely display ON-OFF by utilizing one or two of red, green and blue displays for a display panel of the simple matrix.